Copying data from mirrored storage to auxiliary storage arrays co-located with primary storage arrays

ABSTRACT

Methods that copy data from mirrored storage to auxiliary storage arrays co-located with primary storage arrays are provided. One method includes requesting a subset of the data from a backup system mirroring the set of data at a remote location in response to detecting an error in a storage device of an array of primary storage devices storing a set of data. The method further includes receiving the subset of the data from the backup system and storing the subset of the data in an array of auxiliary storage devices co-located with the array of primary storage devices in which the subset of the data can correspond to data stored on the storage device. Systems and computer program products for performing the above method are also provided.

FIELD

The subject matter disclosed herein relates to storage networks andsystems and, more particularly, relates to copying data from mirroredstorage to auxiliary storage arrays co-located with primary storagearrays.

BACKGROUND

To prevent data loss, data is often copied or mirrored to one or morebackup storage devices and/or systems. The backup storage device(s) orsystem(s) may be co-located with or remotely located from the primarystorage device(s) and/or system(s).

Typically, mirrored data from the backup storage device(s) and/orsystem(s) is used to recover data when there is full array data loss onthe primary storage device(s) and/or system(s). However, prior recoverytechniques can be inefficient and/or inconvenient.

For instance, when a single array goes offline on the primary site, allthe storage volumes in the same extent pool may become inaccessible.Further, prior recovery technique normally need to copy the entireextent data pool from a secondary site to primary site, which can createunnecessary latency because all the mirrored data is copied back to theprimary site for recovery. Moreover, some users that have only a singlearray offline, may attempt every means possible and/or take high amountsof risk to bring the array back online in an effort to avoid the unduelatency caused by restoring the data from backup.

Another issue that can cause recovery techniques to be inefficientand/or inconvenient occurs when a device in an array is experiencing oneor more errors and is in the process of rebuilding and another device inthe array reports one or more errors that may cause the entire array gooffline in future and/or may cause the device rebuild take a substantialamount of time and/or increase the rebuild time. Here, having multipledevices experience errors and/or being rebuilt during an overlappingperiod of time can adversely impact the performance of a storage networkand/or system. Accordingly, at least some previous storage networks maynot be operating as efficiently and/or effectively as possible.

BRIEF SUMMARY

Methods and systems that copy data to auxiliary storage arraysco-located with primary storage arrays from mirrored storage areprovided. One method includes requesting a subset of the data from abackup system mirroring the set of data at a remote location in responseto detecting an error in a storage device of an array of primary storagedevices storing a set of data. The method further includes receiving thesubset of the data from the backup system and storing the subset of thedata in an array of auxiliary storage devices co-located with the arrayof primary storage devices. In various embodiments, the subset of thedata corresponds to data stored on the storage device.

A system includes a management module that manages an array of primarystorage devices storing a set of data, an error detection module thatdetects errors in the array of primary storage devices, and a secondarybackup module that requests backup data for subsets of the data from aprimary backup module in response to the error detection moduledetecting errors in the array of primary storage devices. In someembodiments, a subset of the data corresponds to data stored on astorage device experiencing an error and/or at least a portion of saidmodules comprise one or more of a set of hardware circuits, a set ofprogrammable hardware devices, and executable code stored on a set ofcomputer-readable storage mediums.

Also disclosed are computer program products comprising acomputer-readable storage medium including program instructions embodiedtherewith that copy data to auxiliary storage arrays co-located withprimary storage arrays from mirrored storage. Some program instructionsare executable by a processor and cause the processor to request asubset of the data from a backup system mirroring the set of data at aremote location in response to detecting an error in a storage device ofan array of primary storage devices storing a set of data. The programinstructions further cause the processor to receive the subset of thedata from the backup system and store the subset of the data in an arrayof auxiliary storage devices co-located with the array of primarystorage devices. In various embodiments, the subset of the datacorresponds to data stored on the storage device.

BRIEF DESCRIPTION OF THE DRAWINGS

So that at least some advantages of the technology may be readilyunderstood, more particular descriptions of the embodiments brieflydescribed above are rendered by reference to specific embodiments thatare illustrated in the appended drawings. Understanding that thedrawings included herein only depict some embodiments, the embodimentsdiscussed herein are therefore not to be considered as limiting thescope of the technology. That is, the embodiments of the technology thatare described and explained herein are done with specificity and detailutilizing the accompanying drawings, in which:

FIG. 1 is a diagram illustrating one embodiment of a storage system;

FIG. 2A is a block diagram illustrating one embodiment of a processorincluded in the storage system of FIG. 1;

FIG. 2B is a block diagram illustrating another embodiment of aprocessor included in the storage system of FIG. 1;

FIG. 3A is a block diagram illustrating one embodiment of a timingdiagram for storing data in a primary site and a backup site;

FIG. 3B is a diagram illustrating an embodiment of an auxiliary storagearray including the same geometry and/or topology as a correspondingprimary storage array;

FIG. 4 is a diagram illustrating another embodiment of an auxiliarystorage array including the same geometry and/or topology as acorresponding primary storage array;

FIGS. 5A through 5I are diagram illustrating various embodiments ofoperations for replacing primary storage volumes and/or primary storagedevices with corresponding auxiliary storage volumes and/or auxiliarystorage devices in one or more primary arrays;

FIG. 6 is a schematic flow diagram of one embodiment of a method thatcan copy data to one or more auxiliary storage arrays co-located withone or more primary storage arrays from a backup site/system includingmirrored data; and

FIG. 7 is a schematic flow diagram of another embodiment of a methodthat can copy data to one or more auxiliary storage arrays co-locatedwith one or more primary storage arrays from a backup site/systemincluding mirrored data.

DETAILED DESCRIPTION

Disclosed herein are various embodiments providing methods, systems, andcomputer program products that copy data to auxiliary storage arraysco-located with primary storage arrays from mirrored storage. Notably,the language used in the present disclosure has been principallyselected for readability and instructional purposes, and not to limitthe scope of the subject matter disclosed herein in any manner.

Reference throughout this specification to “one embodiment,” “anembodiment,” or similar language means that a particular feature,structure, or characteristic described in connection with the embodimentis included in at least one embodiment. Thus, appearances of the phrases“in one embodiment,” “in an embodiment,” and similar language throughoutthis specification may, but do not necessarily, all refer to the sameembodiment, but mean “one or more but not all embodiments” unlessexpressly specified otherwise. The terms “including,” “comprising,”“including,” and variations thereof mean “including but not limited to”unless expressly specified otherwise. An enumerated listing of itemsdoes not imply that any or all of the items are mutually exclusiveand/or mutually inclusive, unless expressly specified otherwise. Theterms “a,” “an,” and “the” also refer to “one or more,” unless expresslyspecified otherwise.

In addition, as used herein, the term “set” can mean “one or more,”unless expressly specified otherwise. The term “sets” can mean multiplesof or a plurality of “one or mores,” “ones or more,” and/or “ones ormores” consistent with set theory, unless expressly specified otherwise.

Further, the described features, advantages, and characteristics of theembodiments may be combined in any suitable manner. One skilled in therelevant art will recognize that the embodiments may be practicedwithout one or more of the specific features or advantages of aparticular embodiment. In other instances, additional features andadvantages may be recognized in certain embodiments that may not bepresent in all embodiments.

The present technology may be a system, a method, and/or a computerprogram product. The computer program product may include acomputer-readable storage medium (or media) including computer-readableprogram instructions thereon for causing a processor to carry outaspects of the present technology.

The computer-readable storage medium can be a tangible device that canretain and store instructions for use by an instruction executiondevice. The computer-readable storage medium may be, for example, but isnot limited to, an electronic storage device, a magnetic storage device,an optical storage device, an electromagnetic storage device, asemiconductor storage device, or any suitable combination of theforegoing. A non-exhaustive list of more specific examples of thecomputer-readable storage medium includes the following: a portablecomputer diskette, a hard disk, a random access memory (“RAM”), aread-only memory (“ROM”), an erasable programmable read-only memory(“EPROM” or Flash memory), a static random access memory (“SRAM”), aportable compact disc read-only memory (“CD-ROM”), a digital versatiledisk (“DVD”), a memory stick, a floppy disk, a mechanically encodeddevice such as punch-cards or raised structures in a groove includinginstructions recorded thereon, and any suitable combination of theforegoing. A computer-readable storage medium, as used herein, is not tobe construed as being transitory signals per se, such as radio waves orother freely propagating electromagnetic waves, electromagnetic wavespropagating through a waveguide or other transmission media (e.g., lightpulses passing through a fiber-optic cable), or electrical signalstransmitted through a wire.

Computer-readable program instructions described herein can bedownloaded to respective computing/processing devices from acomputer-readable storage medium or to an external computer or externalstorage device via a network, for example, the Internet, a local areanetwork, a wide area network and/or a wireless network. The network maycomprise copper transmission cables, optical transmission fibers,wireless transmission, routers, firewalls, switches, gateway computersand/or edge servers. A network adapter card or network interface in eachcomputing/processing device receives computer-readable programinstructions from the network and forwards the computer-readable programinstructions for storage in a computer-readable storage medium withinthe respective computing/processing device.

Computer-readable program instructions for carrying out operations ofthe present technology may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, or either source code or object code written in anycombination of one or more programming languages, including an objectoriented programming language such as Smalltalk, C++ or the like, andconventional procedural programming languages, such as the “C”programming language or similar programming languages. Thecomputer-readable program instructions may execute entirely on theuser's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough any type of network, including a local area network (LAN) or awide area network (WAN), or the connection may be made to an externalcomputer (for example, through the Internet using an Internet ServiceProvider). To perform aspects of the present technology, in someembodiments, electronic circuitry including, for example, programmablelogic circuitry, field-programmable gate arrays (FPGA), or programmablelogic arrays (PLA) may execute the computer-readable programinstructions by utilizing state information of the computer-readableprogram instructions to personalize the electronic circuitry.

Aspects of the present technology are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to embodiments of thetechnology. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer-readable program instructions.

These computer-readable program instructions may be provided to aprocessor of a general-purpose computer, special purpose computer, orother programmable data processing apparatus to produce a machine, suchthat the instructions, which execute via the processor of the computeror other programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer-readable program instructionsmay also be stored in a computer-readable storage medium that can directa computer, a programmable data processing apparatus, and/or otherdevices to function in a particular manner, such that thecomputer-readable storage medium including instructions stored thereincomprises an article of manufacture including instructions whichimplement aspects of the function/act specified in the flowchart and/orblock diagram block or blocks.

The computer-readable program instructions may also be loaded onto acomputer, other programmable data processing apparatus, or other deviceto cause a series of operational steps to be performed on the computer,other programmable apparatus or other device to produce a computerimplemented process, such that the instructions which execute on thecomputer, other programmable apparatus, or other device implement thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present technology. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof instructions, which comprises one or more executable instructions forimplementing the specified logical function(s). In some alternativeimplementations, the functions noted in the block may occur out of theorder noted in the figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

To more particularly emphasize their implementation independence, manyof the functional units described in this specification have beenlabeled as modules. For example, a module may be implemented as ahardware circuit comprising custom VLSI circuits or gate arrays,off-the-shelf semiconductors such as logic chips, transistors, or otherdiscrete components. A module may also be implemented in programmablehardware devices such as field programmable gate arrays, programmablearray logic, programmable logic devices or the like.

Modules may also be implemented in software for execution by varioustypes of processors. An identified module of program instructions may,for instance, comprise one or more physical or logical blocks ofcomputer instructions which may, for instance, be organized as anobject, procedure, or function. Nevertheless, the executables of anidentified module need not be physically located together, but maycomprise disparate instructions stored in different locations which,when joined logically together, comprise the module and achieve thestated purpose for the module.

Furthermore, the described features, structures, or characteristics ofthe embodiments may be combined in any suitable manner. In the followingdescription, numerous specific details are provided, such as examples ofprogramming, software modules, user selections, network transactions,database queries, database structures, hardware modules, hardwarecircuits, hardware chips, etc., to provide a thorough understanding ofembodiments. One skilled in the relevant art will recognize, however,that embodiments may be practiced without one or more of the specificdetails, or with other methods, components, materials, and so forth. Inother instances, well-known structures, materials, or operations are notshown or described in detail to avoid obscuring aspects of anembodiment.

The schematic flowchart diagrams and/or schematic block diagrams in theFigures illustrate the architecture, functionality, and operation ofpossible implementations. It should also be noted that, in somealternative implementations, the functions noted in the block may occurout of the order noted in the Figures. For example, two blocks shown insuccession may, in fact, be executed substantially concurrently, or theblocks may sometimes be executed in the reverse order, depending uponthe functionality involved. Although various arrow types and line typesmay be employed in the flowchart and/or block diagrams, they areunderstood not to limit the scope of the corresponding embodiments.Indeed, some arrows or other connectors may be used to indicate only anexemplary logical flow of the depicted embodiment.

A method that can copy data to auxiliary storage arrays co-located withprimary storage arrays from mirrored storage includes requesting asubset of the data from a backup system mirroring the set of data at aremote location in response to detecting an error in a storage device ofan array of primary storage devices storing a set of data. The methodfurther includes receiving the subset of the data from the backup systemand storing the subset of the data in an array of auxiliary storagedevices co-located with the array of primary storage devices. In variousembodiments, the subset of the data corresponds to data stored on thestorage device and/or the array of primary storage devices and the arrayof auxiliary storage devices includes a same geometry.

In some embodiments, storing the subset of the data in the array ofauxiliary storage devices includes storing the subset of the data in asecond storage device of the array of auxiliary storage devices thatcorresponds to the first storage device of the array of primary storagedevices. In additional or alternative embodiments, the method includesreplacing the first storage device in the array of primary storagedevices with the second storage device from the secondary array ofstorage devices.

A system includes a management module that manages an array of primarystorage devices storing a set of data, an error detection module thatdetects errors in the array of primary storage devices, and a secondarybackup module that requests backup data for subsets of the data from aprimary backup module in response to the error detection moduledetecting errors in the array of primary storage devices. In someembodiments, a subset of the data corresponds to data stored on astorage device experiencing an error and/or at least a portion of saidmodules comprise one or more of a set of hardware circuits, a set ofprogrammable hardware devices, and executable code stored on a set ofcomputer-readable storage mediums.

In various embodiments, the system further includes a primary sitecomprising the array of primary storage devices and/or a processorincluding the management module, the error detection module, and thesecondary backup module. The system, in some embodiments, furtherincludes a secondary site comprising a secondary array of storagedevices that mirror the set of data stored on the first set of storagedevices and the primary backup module. Here, the primary backup modulecan manage the second set of storage devices and, in response toreceiving, from the secondary backup module, a request for a subset ofthe data stored in a first storage device experiencing a first error,may transmit the subset of the data to the secondary backup module.

In additional or alternative embodiments, the system includes an arrayof auxiliary storage devices on the primary site in which the secondarybackup module stores the subset of the data received from the primarybackup module in the array of auxiliary storage devices. Here, the arrayof auxiliary storage devices may include the same geometry as the arrayof primary storage devices. Further, the error detection module canidentify the first storage device as experiencing the first error and/orthe secondary backup module stores the subset of the data on a secondstorage device in the array of auxiliary storage devices correspondingto the first storage device in the array of primary storage devices. Inaddition, a processor can further include a replacement module thatreplaces the first storage device in the array of primary storagedevices with the second storage device in the array of auxiliary storagedevices in response to the subset of the data being stored in the secondstorage device.

The system, in various embodiments, further includes a secondary arrayof storage devices located on a same site as the array of primarystorage devices in which the secondary backup module stores a subset ofthe data received from the primary backup module in the secondary arrayof storage devices. In some embodiments, the primary backup module islocated on a different site than the array of primary storage devicesand the secondary array of storage devices. Further, the secondary arrayof storage devices can include the same geometry as the array of primarystorage devices.

In some embodiments, the error detection module can identify a firststorage device in the array of primary storage devices as experiencing afirst error and/or the secondary backup module stores the subset of thedata on a second storage device in the secondary array of storagedevices corresponding to the first storage device in the array ofprimary storage devices. In additional and/or alternative embodiments, aprocessor can further include a replacement module that replaces thefirst storage device in the array of primary storage devices with thesecond storage device in the secondary array of storage devices inresponse to the subset of the data being stored in the second storagedevice.

Also disclosed are computer program products comprising acomputer-readable storage medium including program instructions embodiedtherewith that copy data to auxiliary storage arrays co-located withprimary storage arrays from mirrored storage. Some program instructionsare executable by a processor and cause the processor to request asubset of the data from a backup system mirroring the set of data at aremote location in response to detecting an error in a storage device ofan array of primary storage devices storing a set of data. The programinstructions further cause the processor to receive the subset of thedata from the backup system and store the subset of the data in an arrayof auxiliary storage devices co-located with the array of primarystorage devices. In various embodiments, the subset of the datacorresponds to data stored on the storage device and/or the array ofprimary storage devices and the array of auxiliary storage devicesincludes a same geometry.

In some embodiments, the program instructions that store the subset ofthe data in the array of auxiliary storage devices includes programinstructions that store the subset of the data in a second storagedevice of the array of auxiliary storage devices that corresponds to thefirst storage device of the array of primary storage devices. Inadditional or alternative embodiments, the program instruction furtherinclude program instructions that cause the processor to replace thefirst storage device in the array of primary storage devices with thesecond storage device from the secondary array of storage devices.

With reference now to the figures, FIG. 1 is a diagram illustrating oneembodiment of a storage system 100, which can also be considered astorage network. At least in the illustrated embodiment, the storagesystem 100 includes, among other components, a network 102 coupling asecondary or backup site 104 and a primary site 106 such that the backupsite 104 and the primary site 106 are in communication and can shareresources with one another.

The network 102 may be any suitable wired and/or wireless network 102(e.g., public and/or private computer networks in any number and/orconfiguration (e.g., the Internet, an intranet, a cloud network, etc.))that is known or developed in the future. In various embodiments, thenetwork 102 can comprise a cloud network (IAN), a SAN (e.g., a storagearea network, a small area network, a server area network, and/or asystem area network), a wide area network (WAN), a local area network(LAN), a wireless local area network (WLAN), a metropolitan area network(MAN), an enterprise private network (EPN), a virtual private network(VPN), and/or a personal area network (PAN), among other examples ofcomputing networks and/or or sets of computing devices connectedtogether for the purpose of sharing resources.

A backup site 104 may include any quantity and/or type of computingdevices arranged in any topology that is known or developed in thefuture. At least in the illustrated embodiment, the backup site 104comprises, among other components, a set of backup storage devices 108and a set of processors 110 coupled to and in communication with oneanother.

The set of backup storage devices 108 (also simply referredindividually, in various groups, or collectively as backup storagedevice(s) 108) may include any suitable type of storage device that isknown or developed in the future that can store computer-useable data.In various embodiments, a backup storage device 108 may include one ormore non-transitory computer-usable mediums (e.g., readable, writable,read-writable, etc.), which may include any non-transitory and/orpersistent apparatus or device that can contain, store, communicate,propagate, and/or transport instructions, data, computer programs,software, code, routines, etc., for processing by or in connection witha computer processing device. A backup storage device 108, in furtherembodiments, may include non-transitory memory such as, for example,flash memory (e.g., a solid-state devices (SSD) or other non-volatilestorage devices that store persistent data), a dynamic random accessmemory (DRAM) device, an enhanced dynamic random access memory (EDRAM)device, a static random access memory (SRAM) device, a hard disk drive(HDD), a near-line drive, tape drive (e.g., magnetic and/or virtual),and/or other type(s) (e.g., non-volatile and/or persistent) of memorydevices, etc. that are possible and contemplated herein.

In various embodiments, a backup storage device 108 may includenon-volatile/persistent hardware and/or software configured to performlong-term data storage operations, including, but not limited to, dataarchiving, data backup, data mirroring, replicating data, etc. Forinstance, a backup storage device 108 may include non-volatile and/orpersistent hardware and/or software to perform long-term data storageoperations, which may include write operations, read operations,read-write operations, etc., among other operations.

The set of processors 110 (also simply referred individually, in variousgroups, or collectively as backup storage device(s) 110) may include anysuitable computer processing device and/or system that is known ordeveloped in the future that can perform input/output (I/O) operations(e.g., write operation, read operation, and/or read-write operation,etc.) on the storage device(s) 108 in response to receivingcorresponding I/O requests (e.g., write request, read request, and/orread-write request, etc., respectively).

In some embodiments, a processor 110 includes a primary backup module112 that receives requests to copy/mirror (e.g., a write request) a setof data from a data source and/or the primary site 106. In responsethereto, the primary backup module 112 writes the set of data to one ormore of the backup storage devices 108.

In additional or alternative embodiments, a primary backup module 112receives a request to read (e.g., a read request) a subset of the datamirrored/copied on the set of storage devices 108 from a primary site106. In response thereto, the primary backup module 112 transmits thesubset of data to the primary site 106, as discussed elsewhere herein.

A primary site 106, at least in the illustrated embodiment, includes anarray of primary storage devices 114, an array of auxiliary (AUX)storage devices 116, and a set of processors 118, among other componentsthat are possible and contemplated herein. The array of primary storagedevices 114 (also simply referred individually, in various groups, orcollectively as primary storage device(s) 114) may include any suitabletype of storage device that is known or developed in the future that canstore computer-useable data. In various embodiments, a primary storagedevice 114 may include one or more non-transitory computer-usablemediums (e.g., readable, writable, read-writable, etc.), which mayinclude any non-transitory and/or persistent apparatus or device thatcan contain, store, communicate, propagate, and/or transportinstructions, data, computer programs, software, code, routines, etc.,for processing by or in connection with a computer processing device. Aprimary storage device 114, in further embodiments, may includenon-transitory memory such as, for example, flash memory (e.g., SSD orother non-volatile storage devices that store persistent data), a DRAMdevice, an EDRAM device, a SRAM device, a HDD, a near-line drive, tapedrive (e.g., magnetic and/or virtual), and/or other type(s) (e.g.,non-volatile and/or persistent) of memory devices, etc. that arepossible and contemplated herein.

In various embodiments, a primary storage device 114 may includenon-volatile/persistent hardware and/or software configured to performlong-term data storage operations, including, but not limited to, dataarchiving, data backup, data mirroring, replicating data, etc. Forinstance, a primary storage device 114 may include non-volatile and/orpersistent hardware and/or software to perform long-term data storageoperations, which may include write operations, read operations,read-write operations, etc., among other operations.

The array of auxiliary storage devices 116 (also simply referredindividually, in various groups, or collectively as auxiliary storagedevice(s) 116) may include any suitable type of storage device that isknown or developed in the future that can store computer-useable data.In various embodiments, an auxiliary storage device 116 may include oneor more non-transitory computer-usable mediums (e.g., readable,writable, read-writable, etc.), which may include any non-transitoryand/or persistent apparatus or device that can contain, store,communicate, propagate, and/or transport instructions, data, computerprograms, software, code, routines, etc., for processing by or inconnection with a computer processing device. An auxiliary storagedevice 116, in further embodiments, may include non-transitory memorysuch as, for example, flash memory (e.g., SSD or other non-volatilestorage devices that store persistent data), a DRAM device, an EDRAMdevice, a SRAM device, a HDD, a near-line drive, tape drive (e.g.,magnetic and/or virtual), and/or other type(s) (e.g., non-volatileand/or persistent) of memory devices, etc. that are possible andcontemplated herein.

In various embodiments, an auxiliary storage device 116 may includenon-volatile/persistent hardware and/or software configured to performlong-term data storage operations, including, but not limited to, dataarchiving, data backup, data mirroring, replicating data, etc. Forinstance, an auxiliary storage device 116 may include non-volatileand/or persistent hardware and/or software to perform long-term datastorage operations, which may include write operations, read operations,read-write operations, etc., among other operations.

In some embodiments, an array of auxiliary storage devices 116 includesthe same geometry and/or topology as an array of primary storage devices114. Here, the array of auxiliary storage devices 116 can be considereda set of spare storage devices corresponding to the array of primarystorage devices.

In various embodiments, at least a subset of the auxiliary storagedevices 116 may be empty or do not store data at a given point in time.For instance, an auxiliary storage device 116 may be empty or notstoring data while its corresponding primary storage device 114 isonline and/or functioning properly. In situations in which a primarystorage device 114 is offline and/or otherwise unavailable, thecorresponding auxiliary storage device 116 may store a copy of mirroreddata from a backup site 104, which mirrored data is a copy of the datastored in the primary storage device 114 that is offline and/orotherwise unavailable, as discussed elsewhere herein. That is, datastored in an auxiliary storage device 116 can be considered a copy ofthe copy of the data stored in a primary storage device 114 because thedata in the auxiliary storage device 116 is a copy generated frommirrored data.

The processor(s) 118 may include hardware and/or software to copy datato auxiliary storage devices 116 co-located with primary storage devices114 from mirrored storage (e.g., backup site 104). Referring now to FIG.2A, one embodiment of a processor 118A including, among othercomponents, a management module 202, an error detection module 204, anda secondary backup module 206 is illustrated.

In various embodiments, a management module 202 includes hardware and/orsoftware that manages an array of primary storage devices 114. Forinstance, a management module 202 can manage the primary storagedevice(s) 114 by receiving I/O requests (e.g., read requests, writerequests, read-write requests, etc.) and, in response thereto,performing corresponding I/O operations (e.g., read requests, writerequests, read-write requests, etc., respectively) on the primarystorage device(s) 114.

In some embodiments, a management module 202 may transmit data stored inthe primary storage device(s) 114 to a backup site 104 so that a set ofdata in the primary storage device(s) is copied/mirrored at the backupsite 104 (e.g., a mirrored copy of the data set in the backup storagedevice(s) 108). The data set may be synchronously or asynchronouslycopied/mirrored (e.g., written) to the backup site 104 as the data or asubset thereof is written/stored in the primary storage device(s) 114 atthe primary site 106.

An error detection module 204, in various embodiments, includes hardwareand/or software that detects errors in the primary storage device(s)114. An error may be any type of error that is known or identified inthe future. Examples of an error include, but are not limited to, devicemalfunctions, device failures, anticipated device failures (e.g., afailing device, a device that will/may fail in the future, etc.), adevice going offline, damage to a device, device volume malfunctions,device volume failures, anticipated device volume failures (e.g., afailing volume, a volume that will/may fail in the future, etc.), avolume going offline, damage to a volume, error codes (e.g., Key CodeQualifiers (KCQs)), and/or device/volume latency issues, etc., amongother types of error that are possible and contemplated herein.

In some embodiments, an error detection module 204 can identify aprimary storage device 114 in an array of primary storage devices 114that is experiencing an error. In additional or alternative embodiments,an error detection module 204 can identify a primary storage volume(e.g., a magnetic and/or virtual volume) in an array of primary storagevolumes of a primary storage device 114 that is experiencing an error.

A secondary backup module 206, in various embodiments, includes hardwareand/or software that requests backup/mirrored data from a backup site104. Further, the secondary backup module 206 includes hardware and/orsoftware that understands and/or knows that the array of primary storagedevice(s) 114 and the array of auxiliary storage device(s) 114 includethe same geometry and/or topology and can correlate pairs ofcorresponding storage devices and/or storage volumes in the sets ofprimary storage devices 114 and auxiliary storage devices 118.

In various embodiments, a secondary backup module 206 requests subsetsof the data that is stored (e.g., mirrored/copied) in the backup storagedevice(s) 108 in response to an error detection module detecting errorsin the array of primary storage devices 114. For example, in response toan error detection module 204 identifying/determining that a particularprimary storage device 114 is experiencing an error, a secondary backupmodule 206 will request that the backup site 104 (e.g., processor(s)110) transmit a subset of the data stored (copied/mirrored) in thebackup storage device(s) 108 that corresponds to the data stored in theparticular primary storage device 114 that is experiencing the detectederror be transmitted to the primary storage site 106. In response toreceipt of the mirrored subset of data (e.g., the mirrored datacorresponding to the data stored in the primary storage device 114 thatis experiencing the error), a secondary backup module 206 will write(e.g., store, copy, mirror, etc.) the subset of the mirrored data to anauxiliary storage device 116 in the array of auxiliary storage devices116 that corresponds to the primary storage device 114 that isexperiencing the error in the array of primary storage devices 114.

In another non-limiting example, in response to an error detectionmodule 204 identifying/determining that a particular storage volume inan array of storage volumes on a primary storage device 114 isexperiencing an error, a secondary backup module 206 will request thatthe backup site 104 (e.g., processor(s) 110) transmit a subset of thedata stored (copied/mirrored) in the backup storage device(s) 108 thatcorresponds to the data stored in the particular storage volume that isexperiencing the detected error be transmitted to the primary storagesite 106. In response to receipt of the mirrored subset of data (e.g.,the mirrored data corresponding to the data stored in the storage volumethat is experiencing the error), a secondary backup module 206 willwrite (e.g., store, copy, mirror, etc.) the subset of the mirrored datato a pseudo or auxiliary storage volume in the array of auxiliarystorage devices 116 that corresponds to the storage volume that isexperiencing the error.

In some embodiments, a secondary backup module 206 requests data that isstored (e.g., mirrored/copied) in the backup storage device(s) 108 inresponse to an error detection module detecting errors in the array ofprimary storage devices 114. For example, in response to an errordetection module 204 identifying/determining that a particular primarystorage device 114 is experiencing an error, a secondary backup module206 will request that the backup site 104 (e.g., processor(s) 110)transmit the data stored (copied/mirrored) in the backup storagedevice(s) 108 and the backup site 104 will transmit the full mirroredset of data stored on the backup site 104. In response to receipt of thefull mirrored set of data, a secondary backup module 206 will write(e.g., store, copy, mirror, etc.) the full set of mirrored data to thearray of auxiliary storage devices 116. Here, the auxiliary device 116that corresponds to the to the primary storage device 114 that isexperiencing the error will have the subset of the mirrored data thatcorresponds to the data in the primary storage device 114 that isexperiencing the error written to it. Further, the remaining mirroreddata in the full set of mirrored data that was transmitted from thebackup site 104 that corresponds to the primary storage device(s) 114that are functioning properly and/or are not experiencing an error maynot be written to the primary site 106, any of the auxiliary devices 116and/or any of the primary devices 116 (e.g., a no operation,non-operation, etc.). In this manner, the backup site 104 may be unawarewhich mirrored data (or subset of mirrored data) is being copied to theprimary site 106 and/or primary storage device 114, which primarystorage device 114 is experiencing an error, and/or which auxiliarydevice 116 is receiving the copy of the mirrored data/mirrored datasubset.

In a further non-limiting example, in response to an error detectionmodule 204 identifying/determining that a particular storage volume inan array of storage volumes on a primary storage device 114 isexperiencing an error, a secondary backup module 206 will request thatthe backup site 104 (e.g., processor(s) 110) transmit the data stored(copied/mirrored) in a sub-range of storage volumes that correspond tothe data in the array of auxiliary storage devices 116 in the backupstorage device(s) 108 and the backup site 104 will transmit the subsetof data stored on the sub-range of storage volumes. In response toreceipt of the subset of data, a secondary backup module 206 will write(e.g., store, copy, mirror, etc.) the subset of mirrored data to one ormore storage volumes in the primary storage device(s) 114 and anauxiliary storage volume in an auxiliary storage device 116 thatcorresponds to the storage volume that is experiencing the error willhave the mirrored data that corresponds to the data in the storagevolume that is experiencing the error written to it. Further, theremaining mirrored data in the set of mirrored data that was transmittedfrom the backup site 104 that corresponds to the storage volume(s) thatare functioning properly and/or are not experiencing an error may not bewritten to the primary site 106, any of the storage volumes in theauxiliary device(s) 116 and/or any of the storage volumes in the primarydevice(s) 116 (e.g., a no operation, non-operation, etc.). In thismanner, the backup site 104 may be unaware which mirrored data (orsubset of mirrored data) is being copied to the primary site 106,primary storage device 114, and/or storage volume, which primary storagedevice 114 is experiencing an error, and/or which auxiliary device 116is receiving the copy of the mirrored data/mirrored data subset.

The embodiments discussed in the above examples may provide severaladvantages and/or improvements over conventional storage and/or recoverytechniques. For instance, some embodiments in which the backup sitetransmits an identified subset of the mirrored data can increaseefficiency and/or can eliminate or at least reduce the amount of time orlatency issues associated with copying data due to difference in thetime it takes to transmit a subset of the mirrored data compared to thetime it takes to transmit a full copy of the mirrored data. Further,some embodiments in which the full copy of the mirrored data canincrease efficiency and/or accuracy due to the ease it requesting a datacopy since a specific subset and/or amount of data may not be identifiedand/or it can be simpler to implement full copy writes compared tocopying a subset of the mirrored data. While some advantages areidentified and discussed herein, the various embodiments are limited tosuch advantages and/or improvements, but rather, the various embodimentscontemplate all of the possible advantages and/or improvements that canbe provided by the various embodiments.

Referring to FIG. 2B, FIG. 2B is a block diagram of another embodimentof a processor 118B. At least in the illustrated embodiment, theprocessor 118B includes, among other components, a management module202, an error detection module 204, and a secondary backup module 206similar to the processor 118A of FIG. 2A and further includes areplacement module 208.

A replacement module 208, in various embodiments, includes hardwareand/or software that replaces primary storage devices 114 and/or storagevolumes on a primary storage device 114 that are experiencing one ormore errors. The hardware and/or software can also replace primarystorage devices 114 and/or storage volumes that are in the process ofbeing rebuilt.

In some embodiments in which an array of auxiliary storage devices 118includes the same geometry and/or topology as an array of primarystorage devices 114, a replacement module 208 replaces primary storagedevices 114 in the array of primary storage devices 114 withcorresponding auxiliary storage devices 116 in the array of auxiliarystorage devices 116. The replacement module 208 can replace multipleprimary storage devices 114 in an array of storage devices 114 inparallel (e.g., at the same or at substantially the same time) and/or inseries (e.g., in succession, in a sequence, etc.).

In additional or alternative embodiments in which an array of auxiliarystorage devices 118 includes the same geometry and/or topology as anarray of primary storage devices 114, a replacement module 208 replacesstorage volumes 114 in a primary storage device 114 with correspondingauxiliary storage volumes in an auxiliary storage device 116. Thereplacement module 208 can replace multiple storage volumes in theprimary storage device 114 in parallel (e.g., at the same or atsubstantially the same time) and/or in series (e.g., in succession, in asequence, etc.).

A replacement module 208, in some embodiments, can replace primarystorage devices 114 with corresponding auxiliary storage devices 116 andstorage volumes in primary storage devices 114 with correspondingauxiliary storage volumes in corresponding auxiliary storage devices116. For instance, the replacement module 208 can replace, in paralleland/or in series, multiple primary storage devices 114, multiple storagevolumes, a primary storage device 114 and a storage volume, multipleprimary storage devices 114 and a storage volume, a primary storagedevice 114 and multiple storage volumes, and/or multiple primary storagedevices and multiple storage volumes.

In additional or alternative embodiments, a replacement module 208 canreplace multiple arrays of primary storage devices 114 with multiplecorresponding arrays of auxiliary storage devices 116. The arrays ofprimary storage devices 114 may be replaced in parallel and/or inseries. Further, a replacement module 208 can replace one or morestorage volumes in one or more primary storage devices 114 of the arraysof primary storage devices 114 and/or one or more primary storagedevices 114 in the arrays of primary storage devices 114 in paralleland/or in series.

For instance, a replacement module 208 can replace one or more storagevolumes in the same, different, and/or multiple primary storage devices114 in the same, different, and/or multiple arrays of primary storagedevices in parallel and/or in series. Further, a replacement module 208can replace one or more primary storage devices 114 in the same,different, and/or multiple arrays of storage devices 114 in paralleland/or in series. Moreover, a replacement module 208 can replace one ormore arrays of storage devices 114 in parallel and/or in series.

FIG. 3A illustrates one embodiment of a timing diagram 300 for storingdata in a primary site 106 and a backup site 104. At least in theillustrated embodiment, a set of data is stored in volumes 302A, 302B, .. . 302 n (simply referred individually, in various groups, orcollectively as primary volume(s) 302 or primary storage volume(s) 302)on the primary site 106 (T0).

The primary volumes 302 may be synchronously and/or asynchronouslymirrored/copied to the backup site 104 (T1) to create volumes 304A,304B, . . . 304 n (simply referred individually, in various groups, orcollectively as backup volume(s) 304 or backup storage volume(s) 304).The backup volume(s) 304 are copied/mirrored back to the primary site106 (T2) to create volumes 306A, 306B, . . . 306 n (simply referredindividually, in various groups, or collectively as auxiliary volume(s)306 or auxiliary storage volume(s) 306).

The backup volume(s) 304 may include the same geometry and/or topologyas the primary volume(s) 302 and, in some embodiments, can include adifferent geometry and/or topology than the primary volume(s) 302 (andthe auxiliary volume(s) 306). As shown in FIG. 3B, the auxiliaryvolume(s) 306 include the same geometry and/or topology as the primaryvolume(s) 302 and can be considered one or more spare volumes for theprimary volume(s) 302.

As further shown in FIG. 4, the corresponding pairs of volume302/auxiliary volume 306 include the same strides 400A, 400B, . . . 400n (simply referred individually, in various groups, or collectively asstride(s) 400). As shown, the corresponding strides 400 are stored incorresponding storage locations in each volume 302/auxiliary volume 306pair.

Referring now to FIGS. 5A through 5I, FIGS. 5A through 5I illustratevarious non-limiting examples of replacing primary storage volumes 302and/or primary storage devices 114 in accordance with variousembodiments discussed herein. In FIG. 5A, a replacement module 208replaces a volume 302 or primary storage device 114 (with the volume302) in a primary array 302/114 with a corresponding auxiliary volume306 or auxiliary storage device 116 in an auxiliary array 306/116.

The volume 302 or primary storage device 114 is replaced in response toan error detection module 204 detecting/determining an error in thevolume 302 and/or primary storage device 114. Further, the volume 302 orprimary storage device 114 is replaced subsequent to a secondary backupmodule 206 requesting and receiving a mirrored copy of the data storedin the volume 302 or primary storage device 114 from a backup site 104.The error may be any type of error that a volume 302 and/or primarystorage device 114 can experience and be detected by an error detectionmodule 208, as discussed elsewhere herein.

The example illustrated in FIG. 5B is similar to the example illustratedin FIG. 5A, but illustrates one type of error that can be experienced bya volume 302 or primary storage device 114. In the illustratedembodiment, replacement is initiated by a replacement module 208 inresponse to an error detection module 204 detecting/determining alatency error (e.g., the volume 302 or primary storage device 114 isslow, has stopped, is experiencing a high amount of latency, etc.) inthe volume 302 or primary storage device 114. A latency error may bebased on any suitable time and/or operations metric including, forexample, I/O operations per second (TOPS). Further, the replacementmodule 208 replaces the volume 302 or primary storage device 114subsequent to a secondary backup module 206 requesting and receiving amirrored copy of the data stored in the volume(s) 302 or primary storagedevice(s) 114 from a backup site 104.

The example shown in FIG. 5C is similar to the example illustrated inFIG. 5B, but illustrates a different type of error that can beexperienced by a volume 302 or primary storage device 114. In FIG. 5C,the error being experienced by the volume 302 or primary storage device114 is one or more errors that result in the generation of one or moreerror codes (e.g., KCQ codes, etc.) and/or the generation of greaterthan a predetermined quantity of error codes.

FIG. 5D illustrates an example that is similar to the examplesillustrated in FIGS. 5B and 5C, but illustrates a different type oferror that can be experienced by a volume 302 or primary storage device114. In FIG. 5D, the error being experienced by the volume 302 orprimary storage device 114 is an error detection module 208 detectingthat the volume 302 or primary storage device 114 is failing and/or willfail in the future. Here, the error detection module 208 can determinethat the volume 302 or primary storage device 114 is failing or willfail shortly utilizing any technique and/or process that is known ordeveloped in the future.

The example shown in FIG. 5E is similar to the examples illustrated inFIGS. 5B through 5D, but illustrates a different type of error that canbe experienced by a volume 302 or primary storage device 114. In FIG.5E, the error being experienced by the volume 302 or primary storagedevice 114 is a device failure or otherwise becoming unavailable. Theerror detection module 208 can determine that the volume 302 or primarystorage device 114 has failed or is otherwise unavailable utilizing anytechnique and/or process that is known or developed in the future.

The example shown in FIG. 5F illustrates replacing a volume 302 orprimary storage device 114 that is being rebuilt with a correspondingauxiliary volume 306 or auxiliary storage device 116. The volume 302 orprimary storage device 114 is replaced by a replacement module 208 inresponse to an error detection module 204 detecting/determining an errorin the volume 302 or primary storage device 114 and the volume 302 orprimary storage device 114 is in the process of being rebuilt. Further,the replacement module 208 replaces the volume 302 or primary storagedevice 114 subsequent to a secondary backup module 206 requesting andreceiving a mirrored copy of the data stored in the volume(s) 302 orprimary storage device(s) 114 from a backup site 104.

In FIG. 5G, a replacement module 208 replaces multiple volumes 302,multiple primary storage devices 114, or a volume 302 and a primarystorage device 114 that are experiencing an error and/or is in theprocess of being rebuilt. The replacement module 208 replaces themultiple volumes 302, multiple primary storage devices 114, or thevolume 302 and the primary storage device 114 with multiple auxiliaryvolumes 306, multiple auxiliary storage devices 116, or an auxiliaryvolume 306 and an auxiliary storage device 116, respectively, which arerepresented in FIG. 5G as AUX volume/device 1 and AUX volume/device 2.Further, the replacement module 208 can replace the volumes 302, primarystorage devices 114, or volume 302 and primary storage device 114 inparallel or in series with one another.

The example shown in FIG. 5H illustrates replacing multiple volumes 302,multiple primary storage devices 114, or a volume 302 and a primarystorage device 114 that are each experiencing an error. The replacementmodule 208 replaces the multiple volumes 302, multiple primary storagedevices 114, or the volume 302 and the primary storage device 114 withmultiple auxiliary volumes 306, multiple auxiliary storage devices 116,or an auxiliary volume 306 and an auxiliary storage device 116,respectively, similar to the example illustrated in FIG. 5G.

In FIG. 5I, a replacement module 208 can replace one or more volumes 302and/or one or more primary storage devices 114 in multiple primaryarrays (e.g., array 1 through array n) similar to the variousembodiments discussed herein with reference to FIGS. 5A through 5H.Further, a replacement module 208 can perform replacement operations inmultiple arrays in parallel and/or in series with respect to one anotherand/or with respect to the volumes 302 and/or primary storage devices114 in each primary array.

For example, a replacement module 208 may perform replacement operationson primary array 1 and primary array n in parallel with respect to oneanother, perform the respective replacement operations for volumes 302and/or storage devices 114 in array 1 in series with respect to oneanother, and perform the respective replacement operations for volumes302 and/or storage devices 114 in array 1 in parallel with respect toone another. In another example, a replacement module 208 may performreplacement operations on primary array 1 and primary array n in serieswith respect to one another, perform the respective replacementoperations for volumes 302 and/or storage devices 114 in array 1 inparallel with respect to one another, and perform the respectivereplacement operations for volumes 302 and/or storage devices 114 inarray 1 in parallel with respect to one another. As can be appreciated,other examples including various combinations of replacement module(s)208 performing replacement operations on multiple primary arrays inparallel and/or in series are possible and contemplated herein.

The various embodiments discussed above with reference to FIGS. 5Athrough 5I may provide several advantages and/or improvements over priorstorage and/or recovery techniques. For instance, after a primarystorage device 114 is replaced by an auxiliary device 116 and/or avolume 302 is replaced by an auxiliary storage volume 306, the amount oftime to rebuild, recover, and/or repair a primary storage device 114and/or volume 302 can be reduced, often significantly, compared to someconventional techniques that can experience a data loss situation, whichadvantages/improvements can conserve time and/or various resources inthe storage system 100.

With reference to FIG. 6, FIG. 6 is a schematic flow diagram of oneembodiment of a method 600 that can copy data to arrays of auxiliarystorage volumes 306 and/or auxiliary storage devices 116 co-located witharrays of primary storage volumes 302 and/or primary storage devices 114from a backup site 104 including mirrored data. At least in theillustrated embodiment, the method 600 begins by a processor 118requesting a subset of mirrored data stored on a backup site 106 and/orsystem (block 602). The subset of mirrored data is a copy of the datastored in a volume 302 or primary storage device 114 (that includes thevolume 302) that is experiencing an error and/or is in the process ofbeing rebuilt, as discussed elsewhere herein.

Upon receipt of the data subset (block 604), the processor 118 storesthe subset of data in a corresponding auxiliary storage volume 306 orauxiliary storage device 116 (that includes the corresponding auxiliarystorage volume 306) (block 606). In various embodiments, the auxiliarystorage volume 306 or auxiliary storage device 116 (that includes theauxiliary storage volume 306) includes the same geometry and/or topologyas the volume 302 or primary storage device 114 that is experiencing theerror and/or is in the process of being rebuilt, as discussed elsewhereherein.

Referring to FIG. 7, FIG. 7 is a schematic flow diagram of anotherembodiment of a method 700 that can copy data to arrays of auxiliarystorage volumes 306 and/or auxiliary storage devices 116 co-located witharrays of primary storage volumes 302 and/or primary storage devices 114from a backup site 104 including mirrored data. At least in theillustrated embodiment, the method 700 begins by a processor 118detecting an error and/or a rebuild process in one or more volumes 302or primary storage devices 114 in one or more primary arrays (e.g.,array 1 through array n in FIGS. 5H and 5I) (block 702).

In response to detecting the error(s) and/or rebuild process orprocesses, the processor 118 requests a subset of mirrored data storedon a backup site 106 and/or system (block 704). The subset(s) ofmirrored data is/are a copy of the data stored in the volume(s) 302and/or primary storage device(s) 114 (that can include the volume(s)302) that is/are experiencing the error(s) and/or in theprocess/processes of being rebuilt, as discussed elsewhere herein.

Upon receipt of the data subset(s) (block 706), the processor 118 storesthe subset(s) of data in the corresponding auxiliary storage volume(s)306 or auxiliary storage device(s) 116 (that includes the correspondingauxiliary storage volume(s) 306) (block 708). In various embodiments,the auxiliary storage volume(s) 306 and/or auxiliary storage device(s)116 (that includes the auxiliary storage volume(s) 306) include(s) thesame geometry and/or topology as the volume(s) 302 and/or primarystorage device(s) 114 that is/are experiencing the error(s) and/or inthe process/processes of being rebuilt, as discussed elsewhere herein.

Subsequent to receiving the subset(s) of mirrored data from the backupsite 104 and/or system, the processor 118 replaces the volume(s) 302and/or primary storage device(s) 114 in the primary array(s) (block710). The processor 118 can replace the volume(s) 302 and/or primarystorage device(s) 114 in the primary array(s) with correspondingauxiliary volume(s) 306 and/or auxiliary storage devices 116 in anycombination of parallel and/or series replacement operations, asdiscussed elsewhere herein.

The embodiments may be practiced in other specific forms. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the technology is, therefore,indicated by the appended claims rather than by the foregoingdescription. All changes that come within the meaning and range ofequivalency of the claims are to be embraced within their scope.

What is claim is:
 1. A system, comprising: a management module thatmanages an array of primary storage devices storing a set of data; anerror detection module that detects errors in the array of primarystorage devices; and a secondary backup module that requests backup datafor subsets of the data from a primary backup module in response to theerror detection module detecting errors in the array of primary storagedevices, wherein: a subset of the data corresponds to data stored on astorage device experiencing an error, and at least a portion of saidmodules comprise one or more of a set of hardware circuits, a set ofprogrammable hardware devices, and executable code stored on a set ofcomputer-readable storage mediums.
 2. The system of claim 1, furthercomprising: a primary site, including: the array of primary storagedevices, and a processor including the management module, the errordetection module, and the secondary backup module.
 3. The system ofclaim 2, further comprising: a secondary site, including: a secondaryarray of storage devices that mirror the set of data stored on the firstset of storage devices, and the primary backup module, wherein: theprimary backup module manages the second set of storage devices, and inresponse to receiving, from the secondary backup module, a request for asubset of the data stored in a first storage device experiencing a firsterror, transmitting the subset of the data to the secondary backupmodule.
 4. The system of claim 3, further comprising: an array ofauxiliary storage devices on the primary site, wherein: the secondarybackup module stores the subset of the data received from the primarybackup module in the array of auxiliary storage devices.
 5. The systemof claim 4, wherein the array of auxiliary storage devices includes asame geometry as the array of primary storage devices.
 6. The system ofclaim 5, wherein: the error detection module identifies the firststorage device as experiencing the first error; and the secondary backupmodule stores the subset of the data on a second storage device in thearray of auxiliary storage devices corresponding to the first storagedevice in the array of primary storage devices.
 7. The system of claim6, wherein the processor further comprises a replacement module thatreplaces the first storage device in the array of primary storagedevices with the second storage device in the array of auxiliary storagedevices in response to the subset of the data being stored in the secondstorage device.
 8. The system of claim 1, further comprising: asecondary array of storage devices located on a same site as the arrayof primary storage devices wherein: the secondary backup module stores asubset of the data received from the primary backup module in thesecondary array of storage devices.
 9. The system of claim 8, whereinthe primary backup module is located on a different site than the arrayof primary storage devices and the secondary array of storage devices.10. The system of claim 8, wherein the secondary array of storagedevices includes a same geometry as the array of primary storagedevices.
 11. The system of claim 10, wherein: the error detection moduleidentifies a first storage device in the array of primary storagedevices as experiencing a first error; and the secondary backup modulestores the subset of the data on a second storage device in thesecondary array of storage devices corresponding to the first storagedevice in the array of primary storage devices.
 12. The system of claim11, wherein the processor further comprises a replacement module thatreplaces the first storage device in the array of primary storagedevices with the second storage device in the secondary array of storagedevices in response to the subset of the data being stored in the secondstorage device.
 13. A method comprising: in response to detecting anerror in a first storage device of an array of primary storage devicesstoring a set of data, requesting a subset of the data from a backupsystem mirroring the set of data at a remote location; receiving thesubset of the data from the backup system; and storing the subset of thedata in an array of auxiliary storage devices co-located with the arrayof primary storage devices, wherein the subset of the data correspondsto data stored on the first storage device.
 14. The method of claim 13,wherein the array of primary storage devices and the array of auxiliarystorage devices includes a same geometry.
 15. The method of claim 14,wherein storing the subset of the data in the array of auxiliary storagedevices comprises: storing the subset of the data in a second storagedevice of the array of auxiliary storage devices that corresponds to thefirst storage device of the array of primary storage devices.
 16. Themethod of claim 15, further comprising: replacing the first storagedevice in the array of primary storage devices with the second storagedevice from the secondary array of storage devices.
 17. A computerprogram product comprising a computer-readable storage medium includingprogram instructions embodied therewith, the program instructionsexecutable by a processor to cause the processor to: in response todetecting an error in a first storage device of an array of primarystorage devices storing a set of data, request a subset of the data froma backup system mirroring the set of data at a remote location; receivethe subset of the data from the backup system; and store the subset ofthe data in an array of auxiliary storage devices co-located with thearray of primary storage devices, wherein the subset of the datacorresponds to data stored on the first storage device.
 18. The computerprogram product of claim 17, wherein the array of primary storagedevices and the array of auxiliary storage devices includes a samegeometry.
 19. The computer program product of claim 18, wherein theprogram instructions that cause the processor to store the subset of thedata in the array of auxiliary storage devices further comprise programinstructions that causes the processor to: store the subset of the datain a second storage device of the array of auxiliary storage devicesthat corresponds to the first storage device of the array of primarystorage devices.
 20. The computer program product of claim 19, furthercomprising program instructions that further cause the processor to:replace the first storage device in the array of primary storage deviceswith the second storage device from the secondary array of storagedevices.